Treatment of environmental pollutants with mineral ores

Abstract

A method for removing a pollutant from emissions or the environment comprising: contacting a mineral ore or the use of a mineral ore selected from the group consisting of bauxite, modified bauxite and mixtures thereof. Typically, the pollutant is a heavy metal or a microorganism.

Description

[0001] This application claims the benefits of U.S. Provisional Patent Application No. 60 / 363,693, filed Mar. 12, 2002; and U.S. Provisional Patent Application No. 60 / 396,526, filed Jul. 17, 2002. The entire text and drawings of the above mentioned provisional applications are hereby incorporated herein by reference as if completely rewritten herein.FIELD OF THE INVENTION [0002] The present invention discloses the use of several relatively raw materials including bauxite, iron ore (e.g. magnetite, hematite, goethite), feldspar, lignite and mixtures thereof for the amelioration of environmental pollutants and / or emissions. Typical pollutants in the emissions or the environment Include heavy metals such as arsenic, cadmium, chromium, nickel, mercury; microorganisms; organic solvents; and the like. BACKGROUND OF THE INVENTION [0003] Pollutants in or on the ground, or in surface or ground waters pose an increasing threat to the environment. The pollutants may result from industrial disc...

AI Technical Summary

Benefits of technology

[0013] A process for treating gas, water, or soil containing heavy metals to prevent their migration in the environment is disclosed. The process involves contacting the heavy metals with a multi-functional sequestration agent, namely, bauxite or modified bauxite. Bauxite is used in its relatively natural form (except for appropriate size reduction to fit a particular application) or in modified form (for increased efficiency). Modifications to the raw bauxite include, but are not limited to, simple processes, such as wetting with water, mild heating to temperatures below 300° C., and / or soaking in solutions of common acids, bases, or salts. In the current invention, when bauxite is applied for treatment of gases, sulfur is an essential ingredient in the co-precipitation of pollutant metals as sulfides. The sulfur may already be present in the gas stream being treated (as in coal combustion gases) or it may be introduced into the treatment with the bauxite. When bauxite is applied to water or soil environments, sulfur is not an essential ingredient for removal of metal pollutants. An important feature of the current invention for treatment of air, water, or soil matrices, is that bauxite, being a relatively cheap material, is used as a single use reagent. No regeneration or reuse of the bauxite is required and the economics of the process promotes its single use and disposal.

[0014] The relatively unrefined raw minerals bauxite, iron ore (e.g. magnetite, hematite, goethite), feldspar, and lignite are used for in-situ treatment of is pollutants to clean up surface and subsurface environments, such as groundwater, soil, fractured rock, surface water, and sediments. These minerals, in their naturally occurring form, are environmentally benign, commonly available, and relatively inexpensive.

Problems solved by technology

Pollutants in or on the ground, or in surface or ground waters pose an increasing threat to the environment.

The pollutants may result from industrial discharges, accidental spills, mine drainage, mine tailing seepage or leaks and the like.

Typically, large quantities of polluted materials need to be treated so that cost of the treating materials becomes an important factor.

Heavy metals, such as mercury, arsenic, cadmium, chromium, and selenium, are used in a number of manufacturing operations and industrial and consumer products, but are hazardous to human health and the ecosystem when released to the environment.

Many of these previous processes suffer from one or more of the following limitations: 1.

The use of the reagent generates a waste product that interferes with its eventual reuse or disposal.

This increases the complexity of the process and cost of the treatment.

The reagent is relatively expensive and economic use of the reagent requires another process to regenerate and reuse the reagent.

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